1. Field of the Invention
The present invention relates generally to connectors for coaxial cables, and, more particularly, but not by way of limitation, to coupling mechanisms for coaxial cable connectors.
2. History of Related Art
A coaxial cable is generally characterized by having an inner conductor, an outer conductor, and an insulator between the inner and outer conductors. The inner conductor may be hollow or solid. At the end of coaxial cable, a connector is attached forming a coaxial cable assembly and facilitating mechanical and electrical coupling of the coaxial cable to electronic equipment and other cables. The method of and apparatus for the mechanical and electrical coupling of the connector to the coaxial cable has for a number of years been the subject of considerable design innovation. For example, to effectuate electrical contact between the inner contact of the connector and the inner conductor of the cable, the inner contact may be soldered or otherwise secured in some other fashion to the inner conductor. To effectuate electrical contact between the body member of the connector and the outer conductor of the cable, a myriad of design issues arise. One design issue relates to the configuration of the outer conductor of the cable. A connector for a coaxial cable having a helically corrugated outer conductor and a hollow, plain cylindrical inner conductor is, for example, described in U.S. Pat. No. 3,199,061 (Johnson et al.). The Johnson patent describes a self-tapping connector. Such connectors are time-consuming to install and relatively expensive to manufacture. Also, when the inner connector is made of brass, over-tightening causes the threads to strip off the connector rather than the end portion of the inner conductor of the cable, and thus the connector must be replaced.
More recent coaxial connector designs have addressed methods of and apparatus for quickly and easily attaching a connector to a coaxial cable with improved efficiency. U.S. Pat. No. 5,802,710, assigned to the assignee of the present invention, and incorporated herein by reference, teaches a method of attaching a connector to a coaxial cable that allows the depth of the inner contact relative to the body member of the connector to be easily controlled. In this manner, the depth of the inner contact relative to the body member of the connector is consistent from one assembly to the next. The method set forth therein also provides a moisture barrier between the cable and the connector without the use of rubber O-rings, thereby protecting the connector from detrimental environmental conditions.
It may thus be seen that coaxial connector designs must address multiple design aspects. U.S. Pat. No. 5,435,745 (Booth) describes a connector for coaxial cables also having a corrugated outer conductor. The Booth patent discloses a connector with utilizes a nut member which has a longitudinally slotted generally cylindrical barrel portion defining a number of barrel segments for fingers. The inner surface of the barrel segments or fingers are flat, so as to define a composite inner barrel surface which is hexagonal. A tapered bushing or inner surface of the connector engages the outer surface of the barrel and deforms the fingers defined by the slots of the barrel into contact with the corrugated outer conductor.
The need for improved high performance coaxial cable connectors that are easy and fast to install and uninstall, particularly under field conditions, has prompted further design innovation. For example, U.S. Pat. No. 6,109,964 (Kooiman), also assigned to the assignee of the present invention, and incorporated herein by reference, describes a connector assembly for a coaxial cable having an annularly corrugated outer conductor. The connector assembly further includes multiple ball bearings seated in apertures formed within the connector for capture between first and second body members thereof. This design minimizes the possibility of dropping and losing small parts, or making other assembly errors in the field when installing a coaxial connector to a coaxial cable. Such design aspects are critically important in the competitive communication industry where economy, reliability and efficiency are the subject of constant focus.
Another very important design aspect of coaxial connectors has been, and currently is, the coupling mechanism that facilitates an interlocking engagement between mating male and female coupling sections. For example, U.S. Pat. No. 4,508,407 (Ball) describes a connector for coaxial cables having a self-locking design wherein a plurality of balls are spring biased toward a locking ring which is rotatable with a coupling nut of the connector. The locking ring is formed with a circular array of detent recesses with which the balls engage when the coupling nut is rotated.
Another connector design addressing the coupling mechanism is set forth and shown in U.S. Pat. No. 4,493,520 to (Davies). The Davis patent describes a coaxial, push-pull connector utilizing balls sitting in an outside member and inwardly biased by a spring element. This particular design facilitates the mating of first and second connector members and their locking in the mating position. Likewise, U.S. Pat. No. 4,407,529 (Holman) teaches a self-locking coupling nut for electrical connectors. The design provides visual and tactile proof of the locked condition of the connector elements by utilizing a plurality of balls which are cammed into ball receiving grooves.
U.S. Pat. No. 4,824,386 (Souders) teaches a coaxial connector utilizing interlocking balls protruding into a recess of one of the connector members. A pair of ball sockets are formed in an inner casing with each containing a ball therein. A mating sleeve includes a pair of axial grooves which, when aligned with the ball sockets, permit the other one of the pair of mating connectors to be inserted and moved within the inner casing. When the axial grooves are offset in alignment from the ball sockets, the balls protrude into the inner casing hollow interior and retain the other mating connector in a selected one of two positions.
U.S. Pat. No. 5,114,361 to (Houtteman) teaches an arresting mechanism/lock for coaxial plug connectors. Balls are provided in a configuration wherein they are disposed in a protective sleeve and are kept in a locked position by a circularly bent spring that is locked in an outside surrounding flat groove of the protective sleeve. These and related designs exemplify the innovation in the effort for improved high performance coaxial cable connector couplings that are easy and fast to install and uninstall one to the other under field conditions and which may also be economically manufactured. The need for an improved locking mechanism for coupling mating cylindrical connector members of a coaxial connector yet remains. International design specifications have even been developed to establish uniformity. For example, one international harmonization system addressing uniform quality control for electronic components, including coaxial connectors, has been established by the Cenebec Electronic Components Committee (xe2x80x9cCECCxe2x80x9d), based in Europe.
It has been well established that connectors incorporating push-pull coupling assemblies permit faster installation than the threaded coupling assemblies. Typical push-pull couplings also often provide more reliable locking mechanisms because vibrations will have a less tendency to cause disconnection as compared to threaded connectors which are more prone to the deleterious effect of vibration. There are obviously no xe2x80x9ccross-threadingxe2x80x9d problems with push-pull connectors, because such problems are by definition the problem of threaded engagement. Certain ones of these aspects are set forth in the above-referenced CECC standards.
It would be a distinct advantage to provide compliance with quality assurance standards, such as those of the CECC, with a push-pull coaxial connector locking mechanism providing efficient and reliable coupling of male and female connector members under field conditions. Enhanced coupling aspects provide improved reliability. The present invention provides such a reliable, push-pull coaxial connector coupling with a spring biased sleeve which is reciprocally positioned around an outer connector member. The push-pull connector described herein includes at least one locking ball therein positioned to be selectively capturable between an inner and outer cylindrical connector members such that it may be biased into secure engagement therein while providing both locked and unlocked positions therebetween.